1. Field of the Invention
The present invention relates to a drive for a storage medium for locking the drive unit when the storage medium, such as a disc, is being loaded or ejected, and for supporting the drive unit in a resilient state when recording or reading from the storage medium is being carried out.
2. Description of the Related Art
FIG. 11A and FIG. 11B are side views showing a conventional disc drive in action, as an example of a vehicle-mounted drive for a storage medium. In this disc drive, a plurality of trays are provided in a magazine M to be mounted in the drive so as to be drawn out freely, and a disc D is placed on an individual tray T. The drive unit 1, facing the loading position of the magazine M, is provided with a drive chassis 2 and a clamp arm 5 rotatably supported by the drive chassis via an axle 7. The drive chassis 2 is provided with a turntable 3, a spindle motor 4 for rotating the turntable 3, and an optical head mounted thereon. The clamp arm 5 is provided with a damper 6 rotatably supported thereon.
In this disc drive, any one of trays T in the magazine M is selected by the movements of the drive unit 1 in the upward and downward directions of the figure. In the state where the drive unit 1 is halted at the position where a tray is selected, as shown in FIG. 11A, the clamp arm 5 turns upward, the tray T selected from the magazine M is drawn out toward the drive unit 1, and the center of the disc D on the tray T is clamped on the turntable by a damper 6. Upon completion of a driving operation of the disc D, the empty tray T is drawn out on the drive unit 1, and when the tray T reaches below the disc D, the clamp arm 5 moves upward, the damper 6 moves away from the disc D to release the disc D from the state of being clamped, and then the disc D in the free state is placed on the tray T and is returned into the magazine M.
When the disc drive is used as a vehicle-mounted drive, the drive unit 1 is required to be supported resiliently by means of resilient members 8, such as a damper, when the disc D is being loaded and driven as shown in FIG. 11B. By supporting the drive unit 1 resiliently in this way, even when vibration of the vehicle body is transmitted to the drive unit 1, the driving condition of the disc D may be prevented from being affected adversely by the vibration. On the other hand, as shown in FIG. 11A, when the disc D is drawn out from the magazine M, it is required to guide the center of the disc D so as to be located on the turntable 3, and when the disc D on the turntable is returned to the magazine M, it is required to accurately guide the disc D to the prescribed position in the magazine M. To meet this need, it is required to lock the drive chassis 2 of the drive unit 1 which is supported by the resilient members 8.
Conventionally, for locking the drive chassis 2 while the disc D is being loaded or ejected as described above, a means is generally used to lock the drive unit 1 by disposing a locking lever or the like outside the drive unit, and hooking the locking lever on the drive chassis 2 by advancing or rotating the locking lever.
However, there is a recognized disadvantage in that a significant area outside the drive unit 1 for the movement of the locking lever should be reserved when the locking lever is disposed outside the drive unit 1, which limits the arrangement of other components around the drive unit 1 and thus hinders the freedom of design.
In the structure of the type where the locking lever is hooked on the drive chassis 2 by advancing or rotating it outside the drive unit 1, one locking lever locks the drive unit in only one direction. Therefore, in order to lock the drive unit in all directions, it is necessary to dispose a number of locking levers so as to surround the drive unit, and thus the number of components to be provided around the drive unit 1 increases. In contrast, when the number of locking levers is decreased, there is a recognized disadvantage in that when the locking lever is hooked on the drive chassis 2, the drive unit 1 is urged in one direction and the position of the driving unit 1 is displaced, and thus the drive unit 1 cannot be located accurately with respect to the magazine M.
Accordingly, it is an object of the present invention to overcome the problems described above and to provide a drive apparatus for driving a storage medium wherein the drive unit may be locked without any mechanism that substantially projects outside the drive unit so as not to limit the space around the drive unit.
It is another object of the invention to provide a drive apparatus for driving a storage medium wherein the drive may be locked in any direction by one or a small number of locking means so that the drive unit may be stably locked in every direction.
The present invention provides a drive apparatus comprising: a drive unit for recording to or reproducing from the storage medium supported on a base via a resilient member; a locking device for locking the drive unit on the base when the storage medium is loaded on the drive unit and/or when the storage medium is ejected from the drive unit; the locking device comprising: a through hole or non-through recess provided on one of the drive unit and the base; a rotating body provided on the other of the drive unit and the base to be placed in the hole or recess; and a rotating device for rotating the rotating body; the rotating body rotationally switched between a locking position where the drive unit is locked on the base with at least one portion thereof in contact with the hole or the recess and a lock releasing position where the rotating body comes off the wall in the through hole or the recess.
In the invention, by rotating the rotating body in the hole or the recess provided on the drive unit or the base, the drive unit may be locked and released from the locked state. Therefore, there is no need to dispose mechanical components constituting the locking device on the base around the drive unit, and thus the space around the drive unit may be used effectively.
The hole of the present invention may be a hole with a rectangular or triangular shaped opening, or may be a notched hole of which one side is opened on the edge of the drive unit.
For example, as shown in FIG. 10, the rotating body may be constructed in such a manner that the rotating body, when rotated to the locking position, comes into contact with at least two portions on the inner wall of the hole or the recess so that the movement of the drive unit on the base is locked in two different directions. Alternatively, as shown in FIG. 9, the rotating body may be constructed in such a manner that the rotating body, when rotated to the locking position, comes into contact with at least two opposite portions in the inner wall of the hole or the recess so that the movement of the drive unit on the base is locked in the opposite two directions.
In addition, as shown in FIG. 3, it is preferable that the rotating body, when rotated to the locking position, comes into contact with at least three points on the inner wall of the hole or the recess so that the movement of the drive unit on the base is locked in all directions in the plane orthogonal to the axis of rotation of the rotating body.
As shown in FIG. 7, a construction is also possible in which at least a portion of the rotating body, when rotated to the locking position, locks the inner wall of the hole or the recess in the direction parallel to the axis of rotation of the rotating body so that the movement of the drive unit on the base is locked in the direction parallel to the rotating shaft.
This invention is suitable for the case where the storage medium is in the shape of a disc, and the drive unit is provided with a rotating means for rotating the disc-shaped storage medium and a head facing or being in contact with the rotating storage medium. The storage medium may be of a form other than a disc, such as a cassette tape or IC package.
On the drive unit, there is provided a clamp means for holding the center of the disc-shaped storage medium to the rotating means, and the clamp driving means for driving the clamp means may also serve as the rotating device and rotate the rotating body to the lock releasing position when the clamp means is set to the state where the storage medium is held.
As described above, by sharing the rotating device for rotationally switching the rotating body and for actuating other mechanisms, it is not necessary to provide a drive means specifically designed for rotating the rotating body.